30 July 2010
Medical research suggests that people taking calcium supplements have a higher risk of heart attack.
The study, published in the British Medical Journal, found that calcium from dietary sources did not increase the risk.
Calcium supplements are often taken by older people for the prevention and treatment of osteoporosis.
Researchers have been analysing the results of 11 different studies carried out on some 12,000 people.
Those taking supplements equating to 500mg of calcium per day were compared to those not on supplements.
People taking the supplements were found to have about a 30% higher risk of heart attack.
It is understood the supplements increase the levels of calcium circulating in the blood.
Experts believe higher blood serum levels lead to hardening of the arteries, which can cause heart attacks.
The study said diets high in calcium from natural sources do not increase the risk of heart attack.
It recommends that doctors review their use of calcium supplements for managing osteoporosis in older people.
The PDF file shows that excluded from this meta-analysis were those studies which had vitamin D along with Calcium.
The paper noted that vitamin D decreased mortality.
Lancet. 2005 May 7-13;365(9471):1621-8.
Oral vitamin D3 and calcium for secondary prevention of low-trauma fractures in elderly people (Randomised Evaluation of Calcium Or vitamin D, RECORD): a randomised placebo-controlled trial.
Grant AM, Avenell A, Campbell MK, McDonald AM, MacLennan GS, McPherson GC, Anderson FH, Cooper C, Francis RM, Donaldson C, Gillespie WJ, Robinson CM, Torgerson DJ, Wallace WA; RECORD Trial Group.
Health Services Research Unit, University of Aberdeen, UK.
BACKGROUND: Elderly people who have a fracture are at high risk of another. Vitamin D and calcium supplements are often recommended for fracture prevention. We aimed to assess whether vitamin D3 and calcium, either alone or in combination, were effective in prevention of secondary fractures.
METHODS: In a factorial-design trial, 5292 people aged 70 years or older (4481 85% of whom were women) who were mobile before developing a low-trauma fracture were randomly assigned 800 IU daily oral vitamin D3, 1000 mg calcium, oral vitamin D3 (800 IU per day) combined with calcium (1000 mg per day), or placebo. Participants who were recruited in 21 UK hospitals were followed up for between 24 months and 62 months. Analysis was by intention-to-treat and the primary outcome was new low-energy fractures.
FINDINGS: 698 (13%) of 5292 participants had a new low-trauma fracture, 183 (26%) of which were of the hip. The incidence of new, low-trauma fractures did not differ significantly between participants allocated calcium and those who were not (331 12.6% of 2617 vs 367 13.7% of 2675; hazard ratio (HR) 0.94 95% CI 0.81-1.09); between participants allocated vitamin D3 and those who were not (353 13.3% of 2649 vs 345 13.1% of 2643; 1.02 0.88-1.19); or between those allocated combination treatment and those assigned placebo (165 12.6% of 1306 vs 179 13.4% of 1332; HR for interaction term 1.01 0.75-1.36). The groups did not differ in the incidence of all-new fractures, fractures confirmed by radiography, hip fractures, death, number of falls, or quality of life. By 24 months, 2886 (54.5%) of 5292 were still taking tablets, 451 (8.5%) had died, 58 (1.1%) had withdrawn, and 1897 (35.8%) had stopped taking tablets but were still providing data for at least the main outcomes. Compliance with tablets containing calcium was significantly lower (difference: 9.4% 95% CI 6.6-12.2), partly because of gastrointestinal symptoms. However, potentially serious adverse events were rare and did not differ between groups.
INTERPRETATION: The findings do not support routine oral supplementation with calcium and vitamin D3, either alone or in combination, for the prevention of further fractures in previously mobile elderly people. PMID: 15885294